You continue increasing production as long as the marginal income remains positive.
operating income divide by top line
Depending on thestate you are in it could vary dramatically however, i live in Texas and that is about $35059.20 after taxes and $41019.26. again this assuming you live in Texas and work 80 hours a week. No overtime is included in this calculation. Also for those of you wondering how i came up with the number, the tax in Texas is about 17% of your total earnings because Texas does not have a state income tax.
When ATO remains constant.
net income is gross income less expenses